JPH06150040A - Bar code reader - Google Patents

Abstract

PURPOSE:To reduce the cost of the entire device as much as possible while shortening the read complete time of a bar code concerning the bar code reader for reading the post net bar code to form information by combining long and short bars. CONSTITUTION:When a post net bar code 1 is irradiated with light from an LED module 8 through a lens 9 for illumination, the picture of the post net bar code 1 is reduced and irradiated with reflected light from the post net bar code 1 by a lens 2 for image formation and continuously, an image is formed so as to be compressed in the lengthwise direction of the bar by a lens 3 for condense. Then, since the areas of long and short bars constituting the post net bar code 1 are made different for occupying a black part where the reflectance is lowered, a signal level is made low at the long bar and made high at the short bar. Thus, a signal sequence corresponding to the long and short bar arrangement of the post net bar code 1 can be provided from a one- dimensional image sensor 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bar code reader, and is used, for example, in a reader for reading a post net bar code which forms information by a combination of long and short bars.

[0002]

2. Description of the Related Art Conventionally, as a bar code having an information form different from that of a general bar code, there is, for example, a post net bar code 1 used in a US postal system as shown in FIG. This post net barcode 1
Does not form information by combining a plurality of bar widths and space widths like general bar codes,
Information (postal code, etc.) is formed by a combination of long and short bars (spaces have no meaning).

A reading device for reading such a post-net bar code 1 is, for example, as shown in FIG.
5, the one-dimensional photoelectric converter 30 (for example, CC
There is a reading device in which the D linear image sensor) is arranged such that the arrangement direction of the light receiving elements and the longitudinal direction (B direction) of the bar are parallel to each other. In this type of reading device, an object to which the post-net barcode 1 is attached or a reading device including the photoelectric converter 30 is used as the post-net barcode 1
By moving along the array direction (direction A) of
The post-net bar code is obtained by performing a discrimination process in which the reflected light from one bar is received by the photoelectric converter 30 and the length of the bar is discriminated by the difference in the light intensity distribution of the received reflected light for each bar. 1) It recognizes the combination of the whole length.

Other reading devices include, for example,
As shown in FIG. 16, a two-dimensional photoelectric converter 31 (for example, CCD area image sensor) is used to receive the image of the post-net barcode 1 as it is and recognize the combination of long and short of each bar. is there. 15 and 16, the imaging lens 2 provided between the post net barcode 1 and the photoelectric converters 30 and 31 is
The image of the post-net barcode 1 is converted into each photoelectric converter 3
It is an optical system for forming an image at 0, 31.

[0005]

However, in the above-described conventional reader, which is equipped with the one-dimensional photoelectric converter 30, the postnet bar code 1 must be read in order to read the entire image of the post net bar code 1. Since the object to which 1 is attached or the reading device equipped with the photoelectric converter 30 has to be moved, there is a problem that the time required to complete the reading of the post net barcode becomes long.

In addition, in the reading device equipped with the two-dimensional photoelectric converter 31, the post-net bar code reading completion time is short, but an expensive device such as a CCD area image sensor called the two-dimensional photoelectric converter 31. Therefore, there is a problem that the cost of the entire reader increases.

Therefore, the present invention has been made in view of the above problems, and provides a bar code reader capable of shortening the bar code reading completion time and reducing the cost of the whole reader as much as possible. That is the purpose.

[0008]

Therefore, the present invention has been made possible by irradiation means for irradiating a bar code on which information is formed by a combination of lengths of a plurality of bars with light, and irradiation light from this irradiation means. A one-dimensional photoelectric conversion means provided in parallel with the bar array direction for receiving the reflected light from the barcode and outputting an electric signal according to the light intensity of the received reflected light; A light collecting means for collecting the reflected light from the longitudinal direction of the bar on the photoelectric conversion means, and a reading means for reading the content of the bar code based on an electric signal from the photoelectric conversion means.
The barcode reader is characterized by including.

[0009]

With the above structure, the light converging means condenses, for each bar, the reflected light from the longitudinal direction of the bar on the photoelectric conversion means, and the one-dimensional photoelectric conversion means is provided in parallel with the arrangement direction of the bars. Outputs an electric signal according to the light intensity of the received reflected light.

Therefore, when viewed in the longitudinal direction of the bar,
Since the area of the bar is different between the long bar and the short bar, when the reflected light from the longitudinal direction is condensed, the light intensity of the received reflected light is different, so that the photoelectric conversion means outputs the light. The electric signal can output a signal string corresponding to the long and short arrangement of the bar of the bar code.

[0011]

The present invention will be described below based on the embodiments shown in the drawings. In this embodiment, the case where the present invention is applied to an apparatus for reading a post net bar code attached to a mail for the purpose of automating the sorting of mail in the US mail system will be described.

FIG. 1 is an overall configuration diagram showing a first embodiment of the present invention. Note that, in the drawing numbers of FIG. 1, the same numbers as the drawing numbers of FIGS. 15 and 16 indicate the same parts as the drawing numbers of FIGS.

In FIG. 1, the post-net bar code 1
Is a bar code that forms information by a combination of lengths of a plurality of bars, and is attached to mail for the purpose of automating mail sorting in the US mail system, for example. In this automatic sorting of mail, for example, the mail is placed on a conveyor device such as a belt conveyor, and the delivery destination is sorted by reading the post net barcode 1 attached to the mail. The use of the post-net barcode 1 has an advantage that the information can be accurately read even if the transport speed of the transport device changes because the information based on the width of the bar or space is not included unlike general barcodes. .

A bar code reader 4 for reading the post net bar code 1 forms a casing 11, an image sensor 7 which is a one-dimensional photoelectric converter, and an image of the post net bar code 1 on the image sensor 7. An image forming lens 2 for irradiating the post net bar code 1, and an LED module 8 in which a plurality of LEDs are arranged in parallel for irradiating light to the post net bar code 1.
An illumination lens 9 for concentrating the light from the D module 8 on the post net bar code 1, a mirror 10 for changing the optical path of the reflected light from the post net bar code 1 to reach the light receiving system, and a post net bar. A condensing lens 3 that condenses the reflected light from the longitudinal direction of the bar of the code 1 on the image sensor 7, and an electronic control device that reads the information content of the post net bar code 1 based on the electric signal from the image sensor 7. (Hereinafter, referred to as ECU) 5.

The LED module 8 and the illuminating lens 9 correspond to irradiating means, the image sensor 7 corresponds to photoelectric converting means, and the condensing lens 3 corresponds to condensing means.
The ECU 5 corresponds to the reading means.

The condensing lens 3 described above has a cylindrical shape so that the reflected light from the longitudinal direction (B direction) of the bar of the post net bar code 1 is imaged on the image sensor 7 for each bar. I am using a lens. The image sensor 7 has a large number of light receiving elements arranged in a line, and the light receiving elements are arranged so that the direction of arrangement thereof is parallel to the central axis of the cylindrical condensing lens 3 described above. Has been done.

Next, the operation of the above configuration will be described.
Note that FIG. 2 is a configuration diagram showing a configuration of a main part of the first embodiment. In FIGS. 1 and 2, when light is emitted from the LED module 8 toward the post net barcode 1 through the illumination lens 9, the reflected light from the post net barcode 1 forms an image through the mirror 10. Reaching the lens 2. Then, the imaging lens 2 reduces the image of the entire post-net barcode 1 and projects it on the focusing lens 3. Then, the condensing lens 3 reduces the image of the post net barcode 1 so as to compress the image of the post net barcode 1 in the longitudinal direction (B direction) of the bar, and projects the image on the image sensor 7.

Here, as shown in FIG. 3A, since the long bar 1a and the short bar 1b constituting the post net bar code 1 have different areas occupied by the black portions having low reflectance, The light intensities of the reflected light seen in the longitudinal direction of are different. Therefore, when the reflected light in the longitudinal direction of the bar of the post net barcode 1 is condensed by the condensing lens 3 for each bar and is imaged on the image sensor 7,
As shown in FIG. 3B, the signal level corresponding to the long / short arrangement of the bars of the post-net barcode 1 is such that the signal level becomes low in the long bar 1a and becomes high in the short bar 1b. Is output to the ECU 5. Then, the ECU 5 reads the information content of the post net barcode 1 based on this signal sequence and transmits the information to an external device (not shown).

Next, the detailed structure and operation of the above-mentioned ECU 5 will be described. 4 is a block diagram showing a detailed configuration of the ECU 5, FIG. 5 is a circuit configuration diagram showing a specific circuit configuration of the follow-up signal generating circuit 16, and FIG. 6 is C to G in FIG.
It is a time chart which shows the signal state in a point.

In FIGS. 4, 5 and 6, the analog signal train (the solid line portion in FIG. 6B) corresponding to the long and short arrangement of the bars of the post net bar code 1 (FIG. 6A) is the image sensor 7. Output from the tracking signal generation circuit 16
Then, by the cooperation of the diodes 22a and 22b, the capacitor 23, and the operational amplifier 24 shown in FIG. 5, the follow-up signal D (broken line portion in FIG. 6B) that follows the analog signal train C is output. Then, the comparison circuit 17 compares the analog signal sequence C from the image sensor 7 with the follow-up signal D from the follow-up signal generation circuit 16 to generate the binarized signal E (FIG. 6C). Then, in response to the binarized signal E, the monopulse generation circuit 18 sets the monopulse signal F (((FIG. 6) which is at a high level for a fixed time width T from the transition point of the binarized signal E to the space). (D)) is generated.

The sample-hold circuit 19 holds the follow-up signal D from the follow-up signal generating circuit 16 by the single-pulse signal F from the single-pulse generating circuit 18 to generate the sample-hold signal G (FIG. 6 (e)). In the A / D conversion circuit 20, the sample hold signal G is A / D converted (analog signal / digital signal conversion) by the generation of the single pulse signal F. Then, the digital signal A / D converted by the A / D conversion circuit 20 is output to the decoder 21, decoded, and then output to an external device (not shown).

As described above, in the first embodiment, the condensing lens 3 and the image sensor 7 allow
Since the long and short arrays of the bars of the post net barcode 1 can be converted into a signal string having a strong and weak signal level corresponding to the array, one-dimensional reflected light can be obtained while using the one-dimensional image sensor 7. The post net barcode 1 can be read by receiving the light.

Next, a modification of the first embodiment will be described. In the first embodiment described above, the single pulse generation circuit 18 and the sample hold circuit 1 are used as the components of the ECU 5.
Although 9 is shown, as the A / D conversion circuit 18, a high-speed processing A / D conversion circuit that can regard the change of the follow-up signal D from the follow-up signal generation circuit 16 as no change is used. In that case, the single pulse generation circuit 18 and the sample hold circuit 19 may be omitted. In this case, the tracking signal waveform D is A / D-converted by the change of the binarized signal E from the bar to the space. Also, A
Instead of the / D conversion circuit 20, another electronic circuit whose level can be determined may be used.

Further, when the sample-hold circuit 19 having a good sampling response is used, the single pulse generation circuit 18 may be omitted. In this case, the binarized signal E causes the sample and hold circuit 19 to
Can be controlled.

Next, the second embodiment will be described. In the second embodiment, two cylindrical condensing lenses that condense the reflected light in the longitudinal direction of the bar are arranged, so that FIG.
It is intended to increase the difference in the amount of received light between the long bar 1a and the short bar 1b shown in (a).

FIG. 7 is an overall configuration diagram showing a second embodiment of the present invention. In addition, in the drawing numbers of FIG. 7 and FIGS. 8 to 13 which will be described later, the parts having the same numbers as the drawing numbers of FIG. 1 are equivalent to the drawing numbers of FIG.

In FIG. 7, in the bar code reader 4a according to the second embodiment, the central axes of the condenser lenses 3a and 3b are parallel to the arrangement direction of the light receiving elements arranged in the image sensor 7. It is located in. Then, the reflected light from the longitudinal direction of each bar of the post net barcode 1 passes through the image forming lens 2 and is then condensed to a certain degree by the light collecting lens 3a on the light collecting lens 3b.
The light is focused on the image sensor 7 by the focusing lens 3b. In other words, the condensing lens 3a causes the reflected light component that is going to be diffused outside the image forming optical path of the image forming lens 2 to be condensed by cooperation with the condensing lens 3b, and further the condensing lens 3b. Thus, the reflected light from the condenser lens 3a is condensed on the image sensor.

As a result, since more reflected light from the longitudinal direction of the bar can be received on the image sensor 7 than in the above-described first embodiment, the long bar 1a and the short bar shown in FIG. 6 (a) are received. It is possible to increase the difference in the light intensity of the received reflected light with respect to 1b, and it is possible to output a signal string corresponding to the long and short arrangement of the bars.

Next, a third embodiment will be described. In the third embodiment, the condensing lens 3 is arranged at the first position.
This is different from the embodiment, and the condensing lens 3 is arranged between the post net barcode 1 and the imaging lens 2.

FIG. 8 is an overall configuration diagram showing a third embodiment of the present invention. In FIG. 8, the reflected light from the longitudinal direction of the bar of the post net barcode 1 is condensed by the condenser lens 3 and reaches the image forming lens 2. Then, the reflected light from the post-net bar code condensed by the condensing lens 3 becomes the reflected light traveling in the image forming optical path of the image forming lens 2, so that the image forming lens 2 converts this reflected light. The image is formed on the image sensor 7. As a result, the barcode reader 4a of the third embodiment can obtain the same effect as the barcode reader 4 of the first embodiment.

Next, a fourth embodiment will be described. In the fourth embodiment, a SELFOC lens is used in place of the image forming lens 2 and the condenser lens 3 described above.

FIG. 9 is an overall configuration diagram showing a fourth embodiment of the present invention. In FIG. 9, the Selfoc lens 12a,
12b is a post net barcode 1 and an image sensor 7
It is provided between and, so that each incident cross section faces vertically in the longitudinal direction of the bar of the post net barcode,
The emission cross section is arranged on the image sensor 7 so that the images of the post net barcode 1 overlap.

Here, in FIG. 9, for the sake of convenience, the light passing through the SELFOC lenses 12a and 12b is drawn so as to travel linearly, but in reality, as shown in FIG. It advances and reaches the image sensor 7. This is the Selfoc lens 12a, 12b
Is formed so as to increase the refractive index from the axis toward the radial direction. As shown in FIG. 11, the SELFOC lenses 12a and 12b are configured by a large number of rod lenses 12a ₁ arranged side by side. The barcode 32 is formed by the plurality of rod lenses 12a ₁ .
Will be imaged on the image sensor 33.

Next, a fifth embodiment will be described. In the fifth embodiment, when the above-mentioned post-net barcode 1 is read, a determination function for determining whether or not the postnet barcode 1 is read upside down is added to the barcode reader 4 of the first embodiment.

That is, when it is attempted to read the long / short array of bars based on the reflected light in the longitudinal direction of the bars of the post net bar code 1 as in the first embodiment, the post net bar codes 1 are arranged upside down. Even if the reading operation is performed, it may be read without any problem. Then, the post-net barcode 1 which is originally arranged in the code order from left to right is read in the reverse code order from right to left, which causes a problem of erroneous reading. Therefore, a function of determining whether or not the post net barcode 1 is correctly arranged is added. In addition, in this embodiment, the first embodiment is applied, but the same can be applied to the second to fourth embodiments.

FIG. 12 is an overall configuration diagram showing a fifth embodiment of the present invention, and FIG. 13 is a configuration diagram showing a main part configuration of the fifth embodiment. In FIG. 12, a bar code reader 4b has an elliptic cylindrical condensing lens 13a, 13b in addition to the structure of the bar code reader 4 described in the first embodiment in order to determine whether the post net bar code 1 is vertically positioned. Phototransistors 14a and 14b, which are 0-dimensional photoelectric converters, are arranged at the image forming positions of the respective condenser lenses.

When the post-net bar code 1 is arranged in a correct positional relationship, the condenser lens 13a collects the reflected light from the upper portion of the long bar 1a and forms it on the phototransistor 14a. The condenser lens 13b condenses the reflected light from the lower portion of the short bar 1b and the lower portion of the long bar 1a and forms an image on the phototransistor 14b.

When the LED module 8 emits light toward the post net bar code 1 through the illumination lens 9, the reflected light from the post net bar code 1 forms an image through the mirror 10. While reaching the lens 2, the light collecting lenses 13a and 13b reach the phototransistors 14a and 14b, respectively.

Then, as shown in the flowchart (FIG. 14) showing the operation of the ECU 5, the electric signals output from the phototransistors 14a and 14b are first input (step S100), and then the levels of both electric signals are set. The comparison is performed (step S110). At this time, when the post-net barcode 1 is arranged in the correct positional relationship, the level of the electric signal on the side of the phototransistor 14a is smaller than the electric signal on the side of the phototransistor 14b where the area occupied by the black portion having low reflectance is small. At this time, the reading operation is allowed (step S120) because the reading becomes higher.

However, when the post net bar code 1 is upside down, the phototransistor 14a.
Since the level of the electric signal output from the phototransistor 14b is lower than that of the electric signal output from the phototransistor 14b, in this case, the reading operation is performed by electronic scanning in the direction opposite to the reading operation in step 120. (Step S130). By such a series of determination processes, it is possible to determine whether or not the positional relationship of the post net barcode 1 is correct.

Here, the above-described up / down determination processing is performed at an arbitrary position in the post net bar code 1 in the fifth embodiment, but the reflected light from the bar focused on the focusing lenses 13a and 13b is not detected. As shown in FIG. 13, it is sufficient that there is reflected light from at least the area of five bars. That is,
In the post-net barcode 1, the long bars 1a are lined up to four in succession, so one of the five continuous bars is the short bar 1b. Therefore, with this one short bar 1b, the phototransistor 1
Since there is a difference in the level of the electric signals of 4a and 14b, the condensing lenses 13a and 13b should just condense the reflected light from the area | region for at least 5 bars.

In the first to fifth embodiments described above,
Although the LED module 8 is used as the light source, other lighting means such as a light bulb may be used as the light source. Further, the light source may not be built in the barcode reader, and light incident from the outside may be used. Further, the decoder 21 may be arranged not on the inside of the bar code reader but on the side of the external device so that the external device can read the contents of the bar code.

[0043]

As described above, in the present invention, the electric signal output from the photoelectric conversion means by the light converging means and the one-dimensional photoelectric conversion means is a signal corresponding to the long and short arrangement of the bar of the bar code. Since the columns can be output, the reading can be completed quickly without moving the device or the bar code while using a device which is less expensive than the two-dimensional photoelectric conversion device, which is the one-dimensional photoelectric conversion device. There is an excellent effect.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing a first embodiment of the present invention.

FIG. 2 is a configuration diagram showing a configuration of a main part of the first embodiment.

FIG. 3 is an explanatory diagram for explaining a relative relationship between an electric signal when the reflected light in the longitudinal direction of the post net barcode 1 and the bar is condensed.

FIG. 4 is a block diagram showing a detailed configuration of an ECU 5 in the first embodiment.

FIG. 5 is a tracking signal generation circuit 16 according to the first embodiment.
3 is a circuit configuration diagram showing a specific circuit configuration of FIG.

6 is a time chart showing signal states at points C to G in the circuit configuration diagram shown in FIG.

FIG. 7 is an overall configuration diagram showing a second embodiment of the present invention.

FIG. 8 is an overall configuration diagram showing a third embodiment of the present invention.

FIG. 9 is an overall configuration diagram showing a fourth embodiment of the present invention.

FIG. 10 is an explanatory diagram for explaining optical characteristics of a SELFOC lens.

FIG. 11 is an explanatory diagram for explaining an image formation state of a barcode image by a SELFOC lens.

FIG. 12 is an overall configuration diagram showing a fifth embodiment of the present invention.

FIG. 13 is a configuration diagram showing a configuration of a main part of the fifth embodiment.

14 is an EC for determining whether the post net bar code 1 is up or down.
It is a flow chart which shows operation of U5.

FIG. 15 is a schematic configuration diagram showing a first conventional example for reading a post net barcode 1.

FIG. 16 is a schematic configuration diagram showing a second conventional example for reading the post net barcode 1.

[Explanation of symbols]

 1 Post Net Bar Code 2 Imaging Lens 3 Condensing Lens 7 Image Sensor

Claims (1)

[Claims] 1. A irradiating means for irradiating a bar code on which information is formed by a combination of lengths of a plurality of bars with light, and a reflected light from the bar code generated by the irradiating light from the irradiating means. In addition, a one-dimensional photoelectric conversion unit provided in parallel to the arrangement direction of the bars, which outputs an electric signal according to the light intensity of the received reflected light, and for each bar, from the longitudinal direction of the bar. A bar code reading apparatus comprising: a light condensing unit that condenses reflected light on each of the photoelectric conversion units; and a reading unit that reads the content of the bar code based on an electric signal from the photoelectric conversion unit. .